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<h1>pwm.c</h1><a href="pwm_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*********************************************************************************</span>
<a name="l00002"></a>00002 <span class="comment"></span>
<a name="l00003"></a>00003 <span class="comment"> Copyright 2006 MakingThings</span>
<a name="l00004"></a>00004 <span class="comment"></span>
<a name="l00005"></a>00005 <span class="comment"> Licensed under the Apache License, </span>
<a name="l00006"></a>00006 <span class="comment"> Version 2.0 (the "License"); you may not use this file except in compliance </span>
<a name="l00007"></a>00007 <span class="comment"> with the License. You may obtain a copy of the License at</span>
<a name="l00008"></a>00008 <span class="comment"></span>
<a name="l00009"></a>00009 <span class="comment"> http://www.apache.org/licenses/LICENSE-2.0 </span>
<a name="l00010"></a>00010 <span class="comment"> </span>
<a name="l00011"></a>00011 <span class="comment"> Unless required by applicable law or agreed to in writing, software distributed</span>
<a name="l00012"></a>00012 <span class="comment"> under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR</span>
<a name="l00013"></a>00013 <span class="comment"> CONDITIONS OF ANY KIND, either express or implied. See the License for</span>
<a name="l00014"></a>00014 <span class="comment"> the specific language governing permissions and limitations under the License.</span>
<a name="l00015"></a>00015 <span class="comment"></span>
<a name="l00016"></a>00016 <span class="comment">*********************************************************************************/</span>
<a name="l00017"></a>00017 <span class="comment"></span>
<a name="l00018"></a>00018 <span class="comment">/** \file pwm.c </span>
<a name="l00019"></a>00019 <span class="comment">  PWM - Pulse Width Modulation.</span>
<a name="l00020"></a>00020 <span class="comment">  Library of functions for the Make Application Board's PwmOut Subsystem.</span>
<a name="l00021"></a>00021 <span class="comment">  //ToDo: DW choose which functions are public, and confirm/correct annotations</span>
<a name="l00022"></a>00022 <span class="comment">*/</span>
<a name="l00023"></a>00023 
<a name="l00024"></a>00024 <span class="comment">/* Library includes. */</span>
<a name="l00025"></a>00025 <span class="preprocessor">#include &lt;string.h&gt;</span>
<a name="l00026"></a>00026 <span class="preprocessor">#include &lt;stdio.h&gt;</span>
<a name="l00027"></a>00027 
<a name="l00028"></a>00028 <span class="comment">/* Scheduler includes. */</span>
<a name="l00029"></a>00029 <span class="preprocessor">#include "FreeRTOS.h"</span>
<a name="l00030"></a>00030 <span class="preprocessor">#include "task.h"</span>
<a name="l00031"></a>00031 
<a name="l00032"></a>00032 <span class="comment">/* Hardware specific headers. */</span>
<a name="l00033"></a>00033 <span class="preprocessor">#include "Board.h"</span>
<a name="l00034"></a>00034 <span class="preprocessor">#include "AT91SAM7X256.h"</span>
<a name="l00035"></a>00035 
<a name="l00036"></a>00036 <span class="preprocessor">#include "io.h"</span>
<a name="l00037"></a>00037 <span class="preprocessor">#include "config.h"</span>
<a name="l00038"></a>00038 <span class="preprocessor">#include "pwm.h"</span>
<a name="l00039"></a>00039 
<a name="l00040"></a>00040 <span class="keywordtype">int</span> Pwm_GetChannelIo( <span class="keywordtype">int</span> channel );
<a name="l00041"></a>00041 
<a name="l00042"></a>00042 <span class="preprocessor">#define PWM_DUTY_MAX 1024</span>
<a name="l00043"></a>00043 <span class="preprocessor"></span>
<a name="l00044"></a>00044 <span class="preprocessor">#define PWM_COUNT 4</span>
<a name="l00045"></a>00045 <span class="preprocessor"></span>
<a name="l00046"></a>00046 <span class="preprocessor">#define PWM_CHANNEL_0_IO IO_PB19</span>
<a name="l00047"></a>00047 <span class="preprocessor"></span><span class="preprocessor">#define PWM_CHANNEL_1_IO IO_PB20</span>
<a name="l00048"></a>00048 <span class="preprocessor"></span><span class="preprocessor">#define PWM_CHANNEL_2_IO IO_PB21</span>
<a name="l00049"></a>00049 <span class="preprocessor"></span><span class="preprocessor">#define PWM_CHANNEL_3_IO IO_PB22</span>
<a name="l00050"></a>00050 <span class="preprocessor"></span>
<a name="l00051"></a>00051 <span class="keyword">static</span> <span class="keywordtype">int</span> Pwm_Init( <span class="keywordtype">void</span> );
<a name="l00052"></a>00052 <span class="keyword">static</span> <span class="keywordtype">int</span> Pwm_Deinit( <span class="keywordtype">void</span> );
<a name="l00053"></a>00053 
<a name="l00054"></a>00054 <span class="keyword">struct </span>Pwm_
<a name="l00055"></a>00055 {
<a name="l00056"></a>00056   <span class="keywordtype">int</span> users;
<a name="l00057"></a>00057   <span class="keywordtype">int</span> channels;
<a name="l00058"></a>00058   <span class="keywordtype">int</span> duty[ PWM_COUNT ];
<a name="l00059"></a>00059 } Pwm;
<a name="l00060"></a>00060 <span class="comment"></span>
<a name="l00061"></a>00061 <span class="comment">/** \defgroup Pwm</span>
<a name="l00062"></a>00062 <span class="comment">  The Pwm subsystem provides control of the 4 PWM outputs on the SAM7X.</span>
<a name="l00063"></a>00063 <span class="comment">  The Pwm subsystem of the Controller Board can be used independently from the PWM_Out subsystem</span>
<a name="l00064"></a>00064 <span class="comment">  of the Application Board, and in fact the AppBoard PwmOut relies on the Controller Board PWM.</span>
<a name="l00065"></a>00065 <span class="comment">  </span>
<a name="l00066"></a>00066 <span class="comment">  @see PWM_Out</span>
<a name="l00067"></a>00067 <span class="comment">  \ingroup Controller</span>
<a name="l00068"></a>00068 <span class="comment">  @{</span>
<a name="l00069"></a>00069 <span class="comment">*/</span>
<a name="l00070"></a>00070 <span class="comment"></span>
<a name="l00071"></a>00071 <span class="comment">/** </span>
<a name="l00072"></a>00072 <span class="comment">  Set the duty of a PWM device.</span>
<a name="l00073"></a>00073 <span class="comment">  @param index An integer specifying which PWM device (0-3).</span>
<a name="l00074"></a>00074 <span class="comment">  @param duty The duty - (0 - 1023).</span>
<a name="l00075"></a>00075 <span class="comment">  @return 0 on success.</span>
<a name="l00076"></a>00076 <span class="comment">*/</span>
<a name="l00077"></a><a class="code" href="group___pwm.html#g87d5172375c765fb58fe9c8e160b9314">00077</a> <span class="keywordtype">int</span> <a class="code" href="group___pwm.html#g87d5172375c765fb58fe9c8e160b9314" title="Set the duty of a PWM device.">Pwm_Set</a>( <span class="keywordtype">int</span> index, <span class="keywordtype">int</span> duty )
<a name="l00078"></a>00078 {
<a name="l00079"></a>00079   <span class="keywordflow">if</span> ( index &lt; 0 || index &gt; PWM_COUNT )
<a name="l00080"></a>00080     <span class="keywordflow">return</span> <a class="code" href="group___error.html#g097f40c958abccd892d08f31b53c4dde" title="The requested index is not valid.">CONTROLLER_ERROR_ILLEGAL_INDEX</a>;
<a name="l00081"></a>00081 
<a name="l00082"></a>00082   <span class="comment">// Set the duty</span>
<a name="l00083"></a>00083   Pwm.duty[ index ] = duty;
<a name="l00084"></a>00084   AT91C_BASE_PWMC-&gt;PWMC_CH[ index ].PWMC_CUPDR = duty;
<a name="l00085"></a>00085 
<a name="l00086"></a>00086   <span class="keywordflow">return</span> <a class="code" href="group___error.html#gaa42bc036fbba18487ae9a15cd1f2f94" title="All&amp;#39;s well here.">CONTROLLER_OK</a>;
<a name="l00087"></a>00087 }
<a name="l00088"></a>00088 <span class="comment"></span>
<a name="l00089"></a>00089 <span class="comment">/** </span>
<a name="l00090"></a>00090 <span class="comment">  Read the current duty of a PWM device.</span>
<a name="l00091"></a>00091 <span class="comment">  @param index An integer specifying which PWM device (0-3).</span>
<a name="l00092"></a>00092 <span class="comment">  @return The duty - (0 - 1023).</span>
<a name="l00093"></a>00093 <span class="comment">*/</span>
<a name="l00094"></a><a class="code" href="group___pwm.html#gbf3d245344f8c58725d1d0ffc013fedd">00094</a> <span class="keywordtype">int</span> <a class="code" href="group___pwm.html#gbf3d245344f8c58725d1d0ffc013fedd" title="Read the current duty of a PWM device.">Pwm_Get</a>( <span class="keywordtype">int</span> index )
<a name="l00095"></a>00095 {
<a name="l00096"></a>00096   <span class="keywordflow">if</span> ( index &lt; 0 || index &gt; PWM_COUNT )
<a name="l00097"></a>00097     <span class="keywordflow">return</span> <a class="code" href="group___error.html#g097f40c958abccd892d08f31b53c4dde" title="The requested index is not valid.">CONTROLLER_ERROR_ILLEGAL_INDEX</a>;
<a name="l00098"></a>00098 
<a name="l00099"></a>00099   <span class="keywordflow">return</span> Pwm.duty[ index ];
<a name="l00100"></a>00100 }
<a name="l00101"></a>00101 <span class="comment"></span>
<a name="l00102"></a>00102 <span class="comment">/** @}</span>
<a name="l00103"></a>00103 <span class="comment">*/</span>
<a name="l00104"></a>00104 
<a name="l00105"></a>00105 <span class="keywordtype">int</span> Pwm_Start( <span class="keywordtype">int</span> channel )
<a name="l00106"></a>00106 {
<a name="l00107"></a>00107   <span class="keywordtype">int</span> status;
<a name="l00108"></a>00108 
<a name="l00109"></a>00109   <span class="keywordflow">if</span> ( channel &lt; 0 || channel &gt; PWM_COUNT )
<a name="l00110"></a>00110     <span class="keywordflow">return</span> <a class="code" href="group___error.html#g097f40c958abccd892d08f31b53c4dde" title="The requested index is not valid.">CONTROLLER_ERROR_ILLEGAL_INDEX</a>;
<a name="l00111"></a>00111 
<a name="l00112"></a>00112   <span class="comment">// Make sure the channel isn't already being used</span>
<a name="l00113"></a>00113   <span class="keywordtype">int</span> c = 1 &lt;&lt; channel;
<a name="l00114"></a>00114   <span class="keywordflow">if</span> ( c &amp; Pwm.channels )
<a name="l00115"></a>00115     <span class="keywordflow">return</span> <a class="code" href="group___error.html#g5317aab1608afa7507da0214aec0dbab" title="Can&amp;#39;t get a lock on a resource.">CONTROLLER_ERROR_CANT_LOCK</a>;
<a name="l00116"></a>00116 
<a name="l00117"></a>00117   <span class="comment">// lock the correct select line </span>
<a name="l00118"></a>00118   <span class="keywordtype">int</span> io = Pwm_GetChannelIo( channel );
<a name="l00119"></a>00119   <span class="comment">// Try to lock the pin</span>
<a name="l00120"></a>00120   status = Io_Start( io, <span class="keyword">true</span> );
<a name="l00121"></a>00121   <span class="keywordflow">if</span> ( status != <a class="code" href="group___error.html#gaa42bc036fbba18487ae9a15cd1f2f94" title="All&amp;#39;s well here.">CONTROLLER_OK</a> )
<a name="l00122"></a>00122     <span class="keywordflow">return</span> status;
<a name="l00123"></a>00123 
<a name="l00124"></a>00124   <span class="comment">// mark the channel as being used</span>
<a name="l00125"></a>00125   Pwm.channels |= c;
<a name="l00126"></a>00126 
<a name="l00127"></a>00127   <span class="comment">// Disable the PIO for the IO Line</span>
<a name="l00128"></a>00128   Io_PioDisable( io );
<a name="l00129"></a>00129 
<a name="l00130"></a>00130   Io_SetPeripheralA( io );
<a name="l00131"></a>00131 
<a name="l00132"></a>00132   <span class="keywordflow">if</span> ( Pwm.users++ == 0 )
<a name="l00133"></a>00133   {   
<a name="l00134"></a>00134     status = Pwm_Init();
<a name="l00135"></a>00135   }
<a name="l00136"></a>00136 
<a name="l00137"></a>00137   <span class="comment">// Enable the current channel</span>
<a name="l00138"></a>00138   AT91C_BASE_PWMC-&gt;PWMC_ENA = 1 &lt;&lt; channel;
<a name="l00139"></a>00139 
<a name="l00140"></a>00140   <span class="keywordflow">return</span> <a class="code" href="group___error.html#gaa42bc036fbba18487ae9a15cd1f2f94" title="All&amp;#39;s well here.">CONTROLLER_OK</a>;
<a name="l00141"></a>00141 }
<a name="l00142"></a>00142 
<a name="l00143"></a>00143 <span class="keywordtype">int</span> Pwm_Stop( <span class="keywordtype">int</span> channel )
<a name="l00144"></a>00144 {
<a name="l00145"></a>00145   <span class="keywordflow">if</span> ( Pwm.users &lt;= 0 )
<a name="l00146"></a>00146     <span class="keywordflow">return</span> <a class="code" href="group___error.html#gbe5b0c7c2a59668cdeb433375f091c2a" title="This resource has already been stopped too many times.">CONTROLLER_ERROR_TOO_MANY_STOPS</a>;
<a name="l00147"></a>00147 
<a name="l00148"></a>00148   <span class="keywordflow">if</span> ( channel &lt; 0 || channel &gt; PWM_COUNT )
<a name="l00149"></a>00149     <span class="keywordflow">return</span> <a class="code" href="group___error.html#g097f40c958abccd892d08f31b53c4dde" title="The requested index is not valid.">CONTROLLER_ERROR_ILLEGAL_INDEX</a>;
<a name="l00150"></a>00150 
<a name="l00151"></a>00151   <span class="keywordtype">int</span> c = 1 &lt;&lt; channel;
<a name="l00152"></a>00152   <span class="keywordflow">if</span> ( !( c &amp; Pwm.channels ) )
<a name="l00153"></a>00153     <span class="keywordflow">return</span> <a class="code" href="group___error.html#g9ef65cc96e45d38307f661b86c330548" title="Lock attempt was unsuccessful.">CONTROLLER_ERROR_NOT_LOCKED</a>;
<a name="l00154"></a>00154 
<a name="l00155"></a>00155   <span class="comment">// Get the IO</span>
<a name="l00156"></a>00156   <span class="keywordtype">int</span> io = Pwm_GetChannelIo( channel );
<a name="l00157"></a>00157 
<a name="l00158"></a>00158   <span class="comment">// Set the pin to OFF</span>
<a name="l00159"></a>00159   <a class="code" href="group___io.html#g31c976a85de4306c66be6b4c441d3892" title="Turn an IO line on or off.">Io_SetValue</a>( io, <span class="keyword">false</span> );
<a name="l00160"></a>00160   Io_PioEnable( io );
<a name="l00161"></a>00161   
<a name="l00162"></a>00162   <span class="comment">// release the pin</span>
<a name="l00163"></a>00163   Io_Stop( io );
<a name="l00164"></a>00164 
<a name="l00165"></a>00165   Pwm.channels &amp;= ~c;
<a name="l00166"></a>00166 
<a name="l00167"></a>00167   <span class="comment">// Disable the PWM's</span>
<a name="l00168"></a>00168   AT91C_BASE_PWMC-&gt;PWMC_DIS = 1 &lt;&lt; channel;
<a name="l00169"></a>00169 
<a name="l00170"></a>00170   <span class="keywordflow">if</span> ( --Pwm.users == 0 )
<a name="l00171"></a>00171     Pwm_Deinit();
<a name="l00172"></a>00172 
<a name="l00173"></a>00173   <span class="keywordflow">return</span> <a class="code" href="group___error.html#gaa42bc036fbba18487ae9a15cd1f2f94" title="All&amp;#39;s well here.">CONTROLLER_OK</a>;
<a name="l00174"></a>00174 }
<a name="l00175"></a>00175 
<a name="l00176"></a>00176 <span class="keywordtype">int</span> Pwm_Init()
<a name="l00177"></a>00177 {
<a name="l00178"></a>00178   <span class="comment">// Configure PMC by enabling PWM clock</span>
<a name="l00179"></a>00179   AT91C_BASE_PMC-&gt;PMC_PCER = 1 &lt;&lt; AT91C_ID_PWMC;
<a name="l00180"></a>00180 
<a name="l00181"></a>00181   <span class="comment">// Initially they're stopped</span>
<a name="l00182"></a>00182   AT91C_BASE_PWMC-&gt;PWMC_DIS = AT91C_PWMC_CHID0 | AT91C_PWMC_CHID1 | AT91C_PWMC_CHID2 | AT91C_PWMC_CHID3;
<a name="l00183"></a>00183   
<a name="l00184"></a>00184   <span class="comment">// Set the Clock A divider</span>
<a name="l00185"></a>00185   AT91C_BASE_PWMC-&gt;PWMC_MR = (( 4 &lt;&lt; 8 ) | 0x08 );  <span class="comment">// MCK selection or'ed with Divider</span>
<a name="l00186"></a>00186 
<a name="l00187"></a>00187   <span class="comment">// Set the Clock</span>
<a name="l00188"></a>00188   <span class="keywordtype">int</span> i;
<a name="l00189"></a>00189   <span class="keywordflow">for</span> ( i = 0; i &lt; 4; i++ )
<a name="l00190"></a>00190   {
<a name="l00191"></a>00191     AT91S_PWMC_CH *pwm = &amp;AT91C_BASE_PWMC-&gt;PWMC_CH[ i ];
<a name="l00192"></a>00192 
<a name="l00193"></a>00193     pwm-&gt;PWMC_CMR =
<a name="l00194"></a>00194       <span class="comment">// AT91C_PWMC_CPRE_MCK |  // Divider Clock ? </span>
<a name="l00195"></a>00195          AT91C_PWMC_CPRE_MCKA |    <span class="comment">//Divider Clock A</span>
<a name="l00196"></a>00196       <span class="comment">// AT91C_PWMC_CPRE_MCKB;  //Divider Clock B</span>
<a name="l00197"></a>00197       <span class="comment">// AT91C_PWMC_CPD;  // Channel Update Period </span>
<a name="l00198"></a>00198          AT91C_PWMC_CPOL; <span class="comment">// Channel Polarity Invert</span>
<a name="l00199"></a>00199       <span class="comment">// AT91C_PWMC_CALG ; // Channel Alignment Center</span>
<a name="l00200"></a>00200 
<a name="l00201"></a>00201     <span class="comment">// Set the Period register (sample size bit fied )</span>
<a name="l00202"></a>00202     pwm-&gt;PWMC_CPRDR = PWM_DUTY_MAX;
<a name="l00203"></a>00203   
<a name="l00204"></a>00204     <span class="comment">// Set the duty cycle register (output value)</span>
<a name="l00205"></a>00205     pwm-&gt;PWMC_CDTYR = 0;
<a name="l00206"></a>00206 
<a name="l00207"></a>00207     <span class="comment">// Initialise the Update register write only</span>
<a name="l00208"></a>00208     pwm-&gt;PWMC_CUPDR = 0 ;
<a name="l00209"></a>00209   }
<a name="l00210"></a>00210 
<a name="l00211"></a>00211   <span class="keywordflow">return</span> <a class="code" href="group___error.html#gaa42bc036fbba18487ae9a15cd1f2f94" title="All&amp;#39;s well here.">CONTROLLER_OK</a>;
<a name="l00212"></a>00212 }
<a name="l00213"></a>00213 
<a name="l00214"></a>00214 <span class="keywordtype">int</span> Pwm_Deinit()
<a name="l00215"></a>00215 {
<a name="l00216"></a>00216   <span class="comment">// Deconfigure PMC by disabling the PWM clock</span>
<a name="l00217"></a>00217   AT91C_BASE_PMC-&gt;PMC_PCDR = 1 &lt;&lt; AT91C_ID_PWMC;
<a name="l00218"></a>00218 
<a name="l00219"></a>00219   <span class="keywordflow">return</span> <a class="code" href="group___error.html#gaa42bc036fbba18487ae9a15cd1f2f94" title="All&amp;#39;s well here.">CONTROLLER_OK</a>;
<a name="l00220"></a>00220 }
<a name="l00221"></a>00221 
<a name="l00222"></a>00222 <span class="keywordtype">int</span> Pwm_GetChannelIo( <span class="keywordtype">int</span> channel )
<a name="l00223"></a>00223 {  
<a name="l00224"></a>00224   <span class="keywordtype">int</span> io;
<a name="l00225"></a>00225   <span class="keywordflow">switch</span> ( channel )
<a name="l00226"></a>00226   {
<a name="l00227"></a>00227     <span class="keywordflow">case</span> 0:
<a name="l00228"></a>00228       io = PWM_CHANNEL_0_IO;
<a name="l00229"></a>00229       <span class="keywordflow">break</span>;
<a name="l00230"></a>00230     <span class="keywordflow">case</span> 1:
<a name="l00231"></a>00231       io = PWM_CHANNEL_1_IO;
<a name="l00232"></a>00232       <span class="keywordflow">break</span>;
<a name="l00233"></a>00233     <span class="keywordflow">case</span> 2:
<a name="l00234"></a>00234       io = PWM_CHANNEL_2_IO;
<a name="l00235"></a>00235       <span class="keywordflow">break</span>;
<a name="l00236"></a>00236     <span class="keywordflow">case</span> 3:
<a name="l00237"></a>00237       io = PWM_CHANNEL_3_IO;
<a name="l00238"></a>00238       <span class="keywordflow">break</span>;
<a name="l00239"></a>00239     <span class="keywordflow">default</span>:
<a name="l00240"></a>00240       io = 0;
<a name="l00241"></a>00241       <span class="keywordflow">break</span>;
<a name="l00242"></a>00242   }
<a name="l00243"></a>00243   <span class="keywordflow">return</span> io;
<a name="l00244"></a>00244 }
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  <p class="footer">The Make Controller Kit is an open source project maintained by <a href="http://www.makingthings.com">MakingThings</a>.<br />
    MakingThings code is released under the <a href="http://www.apache.org/licenses/LICENSE-2.0.html" target="_blank">Apache 2.0 license</a>.<br />
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		This document was last updated on 5 Dec 2007.
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